Answer Posted / varun rekhi

Onload Tap Changer (OLTC) is used with higher capacity
transformers where HT side voltage variation is frequent
and a nearly constant LT is required. OLTC is fitted with
the transformer itself. Multiple tappings from HV windings
are brought to the OLTC chamber and conacted to fixed
contacts. Moving contacts rotates with the help of rotating
mechanism having a spindle. This spindle can be rotated
manually as well as electrically with a motor. Motor is
connected in such a way that it can rotate in both the
directions so as to rotate the OLTC contacts in clockwise
and anticlock-wise direction. Two push buttons are fitted
on the LCP (local control panel) to rotate the motor and
hence the OLTC contacts in clockwise and anti-clockwise
direction. This movement of contacts thus controls the
output LV voltage of the transformer. So rotating of OLTC
contacts with spindle or push buttons in this way is a
manuall process. In case this process of rotating the OLTC
contacts and hence controlling the LV side voltage is to be
done automatically then a RTCC (Remote Tap Changer
Controller) is installed with the transformer HT Panel. The
RTCC sends signals to LCP and LCP in turn rotates the motor
as per the signals received from the the RTCC


OLTC(on load tap changer)is a mechanism used in transformer
for changing the tapping position on primary side(HV)of
transformer.For any installation mostly in industrial areas
and rural areas the voltage on HV of the transformer will
not be 11kv(taking an example of 11kv System)and
correspondingly the output will not be 433v.To maintain a
constant 11kv/433v the tap changer on the Primary/HV side
of the transformer is either raised or lowered to maintain
constant 11kv input to transformer.Normally it is raised or
lowered in steps of 2.5% of normal KV value.

what is errection pcbs?

1912

---

A mass of 1200g is accelerated at 200 cm/s2by a force. The value of the force required is:(a) 2.4N(b) 2400N(c) 240 kN(d) 0.24N

2961

---

EXPLAIN WHY THE SURGE CURRENT RATING OF AN MCCB OR CIRCUIT BREAKER DECREASES WITH INCREASE IN THE RATING OF MCCB OR CIRCUIT BREAKER.

2013

---

any one can explain what is the size of pvc,armoured, various sizes of powr cable dia?

1918

---

what is the chemical name and formula of refrigarent R-134a.

2280

---

how commomn gate triggering is given for TRIAC ? other thyristor wont be efffected?

2423

---

What are the advantages and disadvantages of closed-loop control system?

1180

---

why Y CONNECTION IS BETTER INTERMS OF EFFICIENCY AND P.F FOR A LAOD LESS THAN 40% AND WHY AFTER DELTA IS BETTER FOR > 40%

1943

---

lorteny method

1994

---

we have 2.2kw,Y,3000rpm motor but 6leads found in TB what happen if we connect in delta?

1883

---

WHAT IS IM (INDEX OF MOUNTING )IN MOTORS

2028

---

What is difference between safe PLC and normal PLC

1599

---

Please define ohm’s law for a.c (alternating current)?

1070

---

TO CALCULATE THE RESISTANCE OF GRR OF HT MOTOR 400KW WHEREAS STATOR VOLTAGE 6.6KV AND ROTOR VOLTAGE 705V AND ROTOR CURRENT IS 346A.

5491

---

SUTIABLE FOR ohm's law super conductor

1939

---